Recreating the Angstrom demo image

I've seen this asked before in the list archives but I haven't found the answer.

Is there a page describing how the 2010.03 Angstrom demo image was created?

I'm just starting out with OpenEmbedded but the base-image recipe has
chosen 2.6.31. I did not expect this as 2.6.32 is already in the demo
image from several months ago. I'm obviously not understanding
something fundamental.

My goal is to build what I've already got running so I can at least
compare code; make small changes, turn on debugging etc, and work
forward from there in small steps.

There is no 2.6.31 kernel for beagle in OE, so why do you say it's building 2.6.31? Did you get a uImage-2.6.31 in deploy?

That's what the build output indicated. What I did was (from memory):

bitbake configure beagleboard
bitbake update
MACHINE=beagleboard bitbake base-image

I got no output in deploy as the build borked on a CRC error in
expat-2.0.1 and it was midnight by then. I need to find an alternate
source for the tarball by the look of it.